The present invention relates generally to fluid treatment devices such as water softeners or alternate contaminant reduction systems, and particularly to a flow-through tank water system for providing service water to points of use based upon both peak demands and daily usage in a domicile or a commercial application such as a food service establishment or other locations where water, particularly treated water is used.
Self-regenerating ion exchange water softeners (hereinafter referred to as “water softeners”) are common water treatment devices used in domiciles and other facilities. Such water softeners have been preferred over alternative water treatment systems, primarily due to their low costs. However, such water softeners have potential environmental problems due to the high level of total dissolved solids (e.g., sodium or potassium chloride salts) discharged as waste during the regeneration process. Secondary uses of waste or reclaimed water, for example crop irrigation, can be impacted by high levels of these dissolved solids in the reclaimed water. As a result, reclaimed water is often regulated to limit such environmental impacts. Moreover, as the usage of reclaimed water increases, and as water supplies become more limited, it is anticipated that usage of water softeners will be more problematic as the quality of reclaimed water is subjected to stricter regulation.
As previously discussed, alternative water treatment systems capable of replacing a water softener and overcoming the problem of a high level of dissolved solids being discharged are known. However, such alternative water treatment systems are disadvantaged in that they are typically more expensive and complicated as compared to existing water softeners. This is particularly true when they are designed to meet a potential peak usage demand in a domicile. Peak usage is defined as when water treatment systems are designed to treat incoming raw water based upon all outlets or points of use in the domicile having water flow through them at the same instant. Conventional ion exchange water softeners can adjust to a wide range of flow rate demands and can be sized to meet peak demands. Such peak usage demands result in water treatment systems being designed to have water treatment capacity far exceeding the actual daily usage requirements of the domicile, and consequently increased costs of typical alternative systems relative to water softeners. By way of example, an alternative water treatment system that is sized to satisfy peak demands of a typical domicile can have a daily water treatment capacity that is 40 to 50 times greater than the domicile's actual daily usage requirements. A typical system designed to meet a 10 gallons per minute water demand would require 14,400 gallons per day capacity even if the actual daily usage is only 300 gallons per day. Consequently, a water treatment system designed to meet peak service water supply demands is generally much more expensive and complicated than a water treatment system that would merely satisfy daily service water usage requirements in the domicile.
One exemplary alternative water treatment system concept applied to address the above-identified problems is the use of an atmospheric storage tank and repressurization pump system. This system can achieve an on-demand instantaneous flow and includes a treatment device, which is installed on the incoming raw water supply that in turn, delivers conditioned water to the atmospheric storage tank. A pump/pressure tank system, commonly used in well water type systems, is then used to deliver service water on demand when a point of use is opened allowing water to flow to the point of use. Typically, the water treatment system is required to be sized to provide for at least daily water usage in the domicile over a twenty-four hour time period. In this manner, the on-demand service water usage requirements of the domicile are satisfied by using the treated water stored in the pressurized storage tank and a repressurization pump system. A repressurization pump of the system only operates when the storage tank pressure is reduced to a pre-set low pressure level. Thus, the repressurization pump is not required to operate every instant there is a demand for service water in the domicile, or to maintain a specific steady pressure in the pressurized storage tank.
Drawbacks of the atmospheric storage tank and delivery pump/pressure type water treatment systems include that they do not deliver service water at a constant pressure, must use an additional pump, require a level control, and they can completely run out of all water if the atmospheric storage tank or make-up/conditioning system is inadequate. An additional drawback is that these systems are exposed to the ambient air, which results in an additional air filtering apparatus being required to prevent contamination of the treated water.
Accordingly, there is a need for an improved water treatment system that can avoid the problems of known water treatment systems as well as alternatives to such systems by supplying the daily requirements of service water to a domicile in a more cost effective and less complicated manner. There is also a need for an improved water treatment system which meets periodic demands for treated water without requiring relatively high volume treatment capacity.